What is a biomass energy extraction device?
It is device that extracts energy from dead biological material. In this case, I am talking about burning wood to create heat. It is a nice "green-wash" for a otherwise dirty topic.
Wood stoves have a bad reputation. They are noted for lots of smoke and particulate emissions that can result in a brown pale hanging over a town or city. However, wood is a great carbon sequestration device, is renewable and therefore sustainable, and can be burned very efficiently.
The problem is that most operators of wood stoves do poor job of burning wood. The design of most wood stoves promote poor combustion. Wood burns best when provided with lots of heat and oxygen. The fact is that most stoves are not provided with an outside air source (good oxygen) and need to be "choked" to inhibit excess heat production. All that leads to a dirty burn.
The key to a good stove is to provide for proper combustion and provide a place for excess heat to be stored. Masonry heaters do an excellent job of this. Unfortunately, masonry heaters are hard to manufacture and transport.
Lately I have been interested in Rocket Mass Heaters. Curious? Go here: http://www.rocketstoves.com/
Again, the problem with these is portability. However, if it can be scaled down to decrease the BTU heat release and provided with minimum thermal mass, it might provide an interesting alternative to conventional stoves.
I have been looking for a better heating solution for my passive solar office. There are some days that I need additional heat. Currently it comes from an electric resistance heater. Some say that is a clean source. Maybe locally...but not downwind from that coal fired electrical generation plant. So, I need an alternate and I am thinking wood. Stay tuned... I have an idea.